21955573 has 2 divisors, whose sum is σ = 21955574. Its totient is φ = 21955572.

The previous prime is 21955567. The next prime is 21955579. The reversal of 21955573 is 37555912.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (21955567) and next prime (21955579).

It can be written as a sum of positive squares in only one way, i.e., 16305444 + 5650129 = 4038^2 + 2377^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21955573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21955579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10977786 + 10977787.

It is an arithmetic number, because the mean of its divisors is an integer number (10977787).

Almost surely, 2^21955573 is an apocalyptic number.

It is an amenable number.

21955573 is a deficient number, since it is larger than the sum of its proper divisors (1).

21955573 is an equidigital number, since it uses as much as digits as its factorization.

21955573 is an evil number, because the sum of its binary digits is even.

The product of its digits is 47250, while the sum is 37.

The square root of 21955573 is about 4685.6774323464. The cubic root of 21955573 is about 280.0151905024.

It can be divided in two parts, 2195557 and 3, that added together give a triangular number (2195560 = T₂₀₉₅).

The spelling of 21955573 in words is "twenty-one million, nine hundred fifty-five thousand, five hundred seventy-three".